As a technique for color conversion of multicolor images, a color converting apparatus that converts an input color signal into a color value within a predetermined range is known. The color converting apparatus includes a multidimensional lookup table and interpolation calculating means. The multidimensional lookup table holds converted color values corresponding to color values of lattice points of a lattice that divides a color space formed by color signal values to be input. The interpolation calculating means obtains, by interpolation, the converted color value of the input color signal on the basis of the converted color values of the lattice points output from the multidimensional lookup table in accordance with the input color signal.
As another technique for color conversion, a color printer including a color correction processing unit is known. The color correction processing unit includes a boundary determining function unit that determines positional relation of an input point relative to a boundary region, the input point being an input color image signal supplied to an input buffer. On the basis of the determination, the color correction processing unit causes a three-dimensional weighting coefficient storage unit to supply converted values of lattice points and weighting coefficients to a color correction processing function unit, the values of the lattice points and the weighting coefficients being used in calculating converted values at two intersecting points. On the basis of the read values, the color correction processing unit causes either an input range processing unit or a boundary region processing unit to perform an interpolating process to generate an appropriate output converted color image.
Related art is disclosed in Japanese Laid-open Patent Publications No. 11-275375 and 2000-244755.